Ve ss overheating

[Mick Finny]

Hey legends I’ve got a 09 ve ss sportswagon engine was hot but temp gauge was halfway, replaced coolant temp sensor and loom plug itwas good for 2 weeks now doing it again, any suggestions of what else could be causing this or maybe faulty sensor, cheers

 

[Fu Manchu]

Stuck thermostat?

 

[J_D 2.0]

engine was hot but temp gauge was halfway

So how are you judging that “the engine is too hot”? If the temp gauge is only at half way it’s within tolerance and there may be no problem at all.

 

[Mick Finny]

So how are you judging that “the engine is too hot”? If the temp gauge is only at half way it’s within tolerance and there may be no problem at all.

Water was boiling in the coolant reservoir

 

[lmoengnr]

Faulty radiator cap?

 

[Fu Manchu]

There could be a blockage somewhere

There could be a new coolant sensor that’s faulty.

There could be a sticking thermostat

Edit: As above, There could be a faulty radiator cap.

However. If by “boiling” you hear bubbling from the reservoir, that will be air being expelled and fluid moving around from expansion after the motor is switched off. That would be normal and especially noticeable after work has been done on the cooling system.

For coolant to boil, the head gasket would long let go and the hoses blown off.

 

[J_D 2.0]

Water was boiling in the coolant reservoir

You mean in the overflow tank? Water can’t boil in the overflow tank as it’s already been expelled from the coolant system.

Sounds like you either need a new radiator cap or you may have a blown head gasket that’s leaking from the combustion chambers to the water jacket.

You can buy test kits that will tell you if it’s a blown gasket. First test would be to run the engine from clap cold with the radiator cap off. If bubbles constantly come out from the radiator and never go away once the engine is warm and coolant is circulating you’ve probably got a blown head gasket.

Replace the cap first and see how you go. Use a genuine cap only as aftermarket ones are problematic.

 

[Skylarking]

Water was boiling in the coolant reservoir

TLDR: replace your radiator cap

Long explanation:

The coolant overflow reservoir can sound like its boiling as the sealed cooling system vents excess coolant into that reservoir…

The fact excess coolant is moved from the sealed system into the overflow reservoir is a normal part of the systems operation since coolant volume increases as temperature increases (and the excess has to go somewhere) . But as the sealed system cools and coolant volume decreases the required coolant is sucked back from the overflow bottle.

What should also be noted is that the boiling point is dependant on pressure, so while the coolant is under pressure at normal operating conditions and thus not boiling, any excess moved into the overflow reservoir will bubble as that bottle is at atmospheric (thus coolant boiling point is lower).

The sealed system is designed to bleed small amounts of air out of the system via the coolant flow into the overflow reservoir but that massive amounts of air within the sealed system (that hasn’t been correctly purged during a coolant change) will cause overheat issues.

Added to the complexity is that the what the instrument cluster temp gauge displays to the driver is dumbed by the ECU so that the driver doesn’t see an accurate analogue temp display but rather they are shown an abstracted indication of engine temperature condition as assessed by ECU.

So the question should be whether the system is building pressure as required (so that coolant boiling point o curs at the correct temperature) and whether the ECU measurement of temperature sender is accurate.

The fact the the primary issue of overheating can be due to low pressure within the sealed system, I’d 1st check the radiator cap and replace with an OEM cap is at all the o-rings look squished or the cap looks suspect in any way. I’d then check that there is no air pockets within the sealed part of the system by doing an air bleed.

@Fu Manchu has a good thread on the subject.

[VZ] - VZ VE VF Alloytec Cooling System Repairs

Helpful basic overview: The following is for both VZ and VE and VF Alloytec motors. The first part of this is on my VZ. Opened the bonnet only to discover a fine line of pink spray from the dry red coolant, all across the engine bay. Lucky to catch it before it let go all together, and no...

forums.justcommodores.com.au

PS: too slow at typing and finding FU’s thread so beaten to the punch, by a few members

 

[Fu Manchu]

Ha. A whole bunch of posts all within a few minutes of each other.

 

[J_D 2.0]

Ha. A whole bunch of posts all within a few minutes of each other.

We are Johnny on the spot to help fellow Holden owners!